I Am Here: One Man’s Experiment With the Location-Aware Lifestyle

Matthew Honan's I Am Here: One Man's Experiment With the Location-Aware Lifestyle article in the Wired Magazine details his experiment with geo applications on his location-equipped mobile devices (iPhone and Android):

I wanted to know more about this new frontier, so I became a geo-guinea pig. My plan: Load every cool and interesting location-aware program I could find onto my iPhone and use them as often as possible.

From this experience, he highlights some of the social and security issues that confronts a person who is very "geo-online." The article has references to various geo-applications for the web and mobile devices. It's a good reference article in the proliferation of geo-applications.